An alternative to corneal transplant for a common corneal disorder

Researchers in the USA have developed a new procedure for treating Fuchs endothelial dystrophy that could be a better option than corneal transplant.

Fuchs endothelial dystrophy is a common condition that can lead to blindness. It’s linked to older age and variations in several genes. About 4 in every 100 people over the age of 40 are affected.

Sight loss in Fuchs dystrophy is due to damage to the innermost layer of the cornea (the endothelium) that gets worse over time. This has traditionally been treated with transplant surgery to replace the whole cornea and, more recently, to replace only the inner layers as this has better results.

Current practice

It’s done by removing a few square millimetres of cells from the endothelium and Decemet’s membrane – one layer of the cornea, just inside the endothelium – in a procedure called ‘Decemet stripping’. The cells are then replaced with healthy ones from a donor (this is what’s known as ‘endothelial keratoplasty’).

However there is always a risk that the transplant will be rejected. And patients at greater risk of the graft being rejected may also need to take drugs that suppress the immune system. This can have serious side-effects such as glaucoma, cataract and higher risk of infection.

The current study looked back over the past 2 years at people treated with a new procedure by Dr Kathryn Colby at Harvard Medical School. It included 11 people with Fuchs dystrophy and cataract. Two participants had both eyes done, so a total of 13 eyes were included.

New procedure

Surgery involved first removing the cataract and replacing the natural lens with an artificial one, followed by Decemet stripping but no transplant. Patients were followed up after 1, 3, 6 and 12 months.

Results published in the journalCornea showed that by 12 months, 10 eyes had clear corneas – 8 with 20/20 vision or better and 2 with retinal conditions that prevented clear vision – and 3 eyes did not respond. These went on to have a standard corneal transplant.

"It's too soon to call this a cure," said Dr Colby. "We performed the first operation just over two years ago. But when it works, it's a wonderful thing. It's quick, inexpensive and it spares patients from having someone else's cells in their eyes, which requires local immunosuppression."

Proof of concept

Dr Dolores M Conroy is Director of Research at Fight for Sight. She said:

“This is a small but very encouraging study showing corneal clearing with endothelial cell repopulation after Decemet stripping without endothelial cell transplantation. This minimally invasive procedure might one day replace the need for endothelial transplantation for Fuchs dystrophy. However, further studies are necessary to understand why some eyes did not respond and which patients might benefit most.

“We need to find a replacement for transplantation both because there is a shortage of donors but also because we know from the Sight Loss and Vision Priority Setting Partnership that corneal transplant and the risk of graft rejection are major concerns for people affected by corneal dystrophy.”